Epidermal growth factor-immobilized surfaces for the selective expansion of neural progenitor cells derived from induced pluripotent stem cells

Neural progenitor cells (NPCs) are considered to be a promising source for stem cell-based regenerative therapy for central nervous disorders. However, the widespread clinical application of NPCs requires another technology that permits the efficient production of pure NPCs in large quantities. In this study, culture substrates were designed by immobilizing epidermal growth factor (EGF) onto the substrate and evaluated for their feasibility of expanding NPCs obtained through the neurosphere culture of induced pluripotent stem (iPS) cells. After three passages we obtained neurospheres that contained cells abundantly expressing an EGF receptor. The neurospheres were dissociated into single cells and seeded onto the EGF-immobilized substrates. It was observed that neurosphere-forming cells seeded and cultured on the EGF-immobilized surface formed a two-dimensional cellular network characteristic of NPCs. These cells were found to be capable of being subcultured, while remaining their proliferation potential. Furthermore, a majority of cells (similar to 99% of total cells) on the substrate was shown to express an NPC marker, nestin, whereas a limited number of cells (similar to 1% of total cells) expressed neuronal marker, beta-tubulin III. These results as a whole demonstrate that the EGF-immobilized substrate allows for iPS cell-derived NPCs to efficiently proliferate while maintaining the undifferentiated state.